#2170 tgz filename bug

[alan birtles]

Compressing a file into a tar.bz2 file then renaming the file to "tgz" causes the filename when extracting the "tgz" file to be incorrect. Renaming to "tar.gz" doesn't show the same issue.

For example extracting "test.txt.tgz" results in a file called "test.txt" which is actually the tar file. Extracting "test.txt.tbz" and "test.txt.tar.gz" both correctly result in "test.txt.tar".

I know this is a strange thing to do but somebody sent us a misnamed file (presumably created on Linux with tar using incorrect flags) and it caused my colleagues some confusion.

[Igor Pavlov]

tgz->tar.gz rule is in gz part of code.
So 7-Zip can't use it for bz2 archive.